Physical Activity and Pacemaker Study

The benefits of habitual physical activity (PA, activities of at least moderate intensity defined as ≥ 3 metabolic equivalents (METs)) are well-recognized. Emerging information from large data sets strongly suggest high levels of sedentary behavior, defined as activities <1.5 METs (equivalent to the amount of energy expended during seated activities such as computer work) increases the risk of diabetes, cardiovascular disease, and death, independent of the amount and intensity PA. The increased risk of sedentary behavior appears to be mediated at least in part by reduced insulin sensitivity, impaired lipid metabolism, increased vascular inflammation, and increased thrombotic tendencies.

The internal accelerometer embedded in Medtronic pacemakers registers, stores, and reports total number of "active time" based on a threshold activity intensity level of approximately 70 steps/min (estimated to be > 1.5 METs). This implanted accelerometer, combined with the regular follow-up required for appropriate care make individuals who have undergone Medtronic pacemaker implantation an ideal population in which to evaluate the impact of altering sedentary behavior on mortality and cardiovascular events.

The hypotheses are as follows:

1. a 12 week intervention to increase moderate intensity physical activity delivered at the point of care in patients with pacemakers will result in parallel increases in active time as measured by the pacemaker and step count as measured by pedometer.
2. the increase in activity measured by both the metrics in hypothesis 1 will be greater than with usual care.

Potential subjects who are interested in the study will have a screening visit to determine whether they meet the inclusion and exclusion criteria. Those who qualify and agree to participate will be randomized into either the Physical Activity Counseling arm (intervention arm) or the Patient Usual Care arm (control arm).

Subjects in the interventional arm will be given a pedometer and physical activity counseling on a regular basis for 3 months. Physical activity data from their external pedometer will be collected every 2 weeks via phone calls. Accelerometry data from the implanted pacemaker will be collected from the subject's medical record as pacemaker interrogations are performed every 3 months as part of routine clinical care. After the initial 3 month interventional phase is complete, these subjects will be followed for another 3 months with collection of pedometer as well as accelerometer data as described above.

Subjects in the control arm will be given pedometers for the week prior to pacemaker interrogation. These subjects will be called to report the number of steps they walked each day prior to the interrogation. Their accelerometry data will be captured through routine clinical pacemaker interrogations.

The primary outcome is the physical activity level in each group as measured by the accelerometer at time 0, 3 months and 6 months. The secondary outcome is the step count in each group as measured by the pedometer at the same time points.

• Physical activity counseling (Behavioral): Subjects in this arm will receive counseling on how to increase their physical activity level.
• Usual care (Behavioral): Subjects will undergo their usual care without intervention

Primary outcomes

• Physical Activity Level as Measured by Embedded Accelerometer [6 months]: This is the daily measured active hours in the device

Secondary outcomes

• Physical Activity Level as Measured by External Pedometer [6 months]: this is a daily step count (one week average)

Sex: All, ages: 55 Years to any

Inclusion Criteria:

* Age > 55 years old
* Clinical indication for placement of permanent pacemaker
* LVEF of ≥ 50% at the time of or within 72 hours of implantation.
* Able to ambulate
* Average active time of ≤ 2 hours/day based on Revo or EnRhythm Accelerometery read out for the 3 month period prior to enrollment
* Able to take 650 steps over 10 minutes following pacemaker implantation (\~2-2.5 mph walking speed)

Exclusion Criteria:

* Follow up for implantation planned at a non-study center at the time of implantation.
* Individuals with and expected life span of 1 year or less at the time of implantation
* Known history of cognitive impairment or inability to follow study procedures

Participant flow

Outcome results

• Physical Activity Level as Measured by Embedded Accelerometer (Primary), Mean, active hours/day: Physical Activity Counseling 1.97 +/- 0.56; Patient Usual Care 1.77 +/- 0.22
• Physical Activity Level as Measured by External Pedometer (Secondary), Mean, steps/day: Physical Activity Counseling 1769 +/- 771; Patient Usual Care 2487 +/- 1800

Adverse events

Time frame: Information on adverse events were recorded over the 1st 12 weeks of the study which contained the intervention

Limitations and caveats: Unable to complete projected enrollment due to difficulties with recruitment

• Results publication: Puppala VK, Hofeld BC, Anger A, Tyagi S, Strath SJ, Fox J, Berger MG, Ahn KW, Widlansky ME. Pacemaker detected active minutes are superior to pedometer-based step counts in measuring the response to physical activity counseling in sedentary older adults. BMC Geriatr. 2020 May 6;20(1):162. doi: 10.1186/s12877-020-01559-y. PMID 32375676

• Study Protocol and Statistical Analysis Plan (PDF, 2016-12-21)

• Michael Widlansky, MD, Principal investigator, Medical College of Wisconsin